Installation
To mitigate the substantial ventilation leakage at Carlyle Towers, CARs were installed behind all the apartments’ kitchen and main exhaust grilles. The CAR dampers were factory calibrated for 30 CFM. Because the air restriction mechanism of the dampers open and close with air pressure, they do not require an external power source to operate and need no manual adjustments to compensate for the variable conditions typically caused by seasonal changes.
Because aeroseal technology works from the inside of the shafts, there was no need to tear down walls or other internal structures. Instead, each ventilation shaft was accessed, one at a time, via its termination point where the roof fans are placed. Each roof fan was removed and a thin, flexible tube was connected to the outside entranceway of the exposed shaft. The delivery tube runs lengthwise back to the aeroseal equipment where a small, window-frame-sized external blower fan is used to push the sealant through the tube and down the shaft. The technician monitored the sealing operation via a laptop computer attached to the mechanical components of the equipment. The computerized delivery system allowed the technician to adjust the procedure and observe the real-time progress of the sealing process.
The technologies are quite complementary from an installation standpoint. The aeroseal process begins by accessing and temporarily blocking each grille, which provides an opportune time to install the CAR dampers, which are also located at each grille site.
Real Results
Through the combined use of these two technologies, the property owners noticed significant differences in the performance of the Carlyle Towers building. Ongoing testing since 2008 demonstrates the retrofit resulted in a 25 percent reduction in gas use for space heating. The duct sealing also allowed for a downsizing of fans from 300 watts to 140 W per fan, a savings of about $7,000 annually in energy costs.
Residents of the Carlyle Towers noticed the difference, as well. Appreciation was expressed by many of the occupants for the improvements made to the building’s heating system—something that was never directly addressed. However, by improving the exhaust system, the retrofit project also helped improve overall heating. Previously, fans were working so hard to exhaust air from the bottom floors that it was drawing cold air from the outside and distributing it throughout the building. The heaters could never keep up. Now that the leaks in the ventilation shafts are sealed and the system is balanced from floor to floor, this problem no longer exists. A significant reduction in fan noise and ambient odors also was immediately apparent.
In addition, the entire project took only weeks to complete, and disruption to tenants was minimal.
With the success of the Carlyle Towers project, this new approach to retrofitting older buildings’ ventilation systems is becoming a game-changer for those who had given up looking for a solution. Lessons learned from this project have influenced the crafting of New York City’s Green Codes Task Force recommendation, HT 6, “Ensure Ventilation Airflow in Residences.”In addition, the National Center for Healthy Housing, Columbia, Md., has published a guide to provide homeowners with more information about these technologies and how they work to improve ventilation and energy efficiency. Lastly, a recent Washington-based U.S. Department of Housing and Urban Development funded study is examining the health benefits of this approach as a means of quantifying solutions to help control health-care costs.
More telling is the fact that since the Carlyle Towers project was completed, more than 5,000 additional apartments have already undergone similar performance upgrading by various contractors throughout the New York City metropolitan region alone. New technologies are providing simple and effective answers to age-old problems and having a real impact on what we can do to improve the safety and performance of today’s buildings.